Occassionaly it's for financial gain or meerly to pass the time, it might even just be collecting bus or train numbers or even Eddie Stobbart truck names.
Essentially we are collecting information around our interests but when you/we really become 'anoraks' it all gets deeper, it comes down to collecting 'labels' either actual labels or markings on a machine part or hallmarks on a piece of silver, after all some collectors will collect the same item that differs only in it's makers stamps or markings.
Myself I have many ties some of which I don't actually like that much but I buy them(cheaply) just for the label on the back because I like it's graphic design.
So here are a few pictures of 'vintage labels'.
woven necktie
Mountain Accessories wool/acrylic shirt from the late 1960's
late 1950's early 60's Harris Tweed label
1950's Society braces
Reynolds 531 tubing transfer from a 1964 E.G Bates touring cycle
Anton Pichler marking in a c 1950's 'trilby' hat
Duratye from the 1940's-50's
Celanese 'Acetate' cravat from the 1940's-50's
Munrospun tie with retailers label 1940's?
Saxony wool tie label 1950's -60's
1960's 'Duggie' cravat label
Lochinvar label c 60's
Harry Fenton one of the original 'Mod' shops label on a knitted tie from the 1960's
Country Life tie label from the late 1960's
label on a 'Sammy' double sided wool and silk? scarf 1960's-70's
Buttons of Luton label on a waistcoat c 1930's-50's
Tooke label on a necktie from the 1940's-50's
Dunn & Co label in a pair of leather gloves c1950's
Swiss made Lucifer front bicycle dynamo light markings c 1964